I really look and try to do things but without success.
It's going a bit in all directions in the conversation and I can not find my way.
Are there any chance to take my problem to zero?
For there I can not do too much.

The errors that you posted are ok, they do not mean that anything is wrong with your setup. They should accour as it means that someone ahs tried to send emails to Linux system users which dont have a mailbox.

So back to your original problem. Login to webmail and send a email to the same address that you used to login to the server and then post the lines that got added to the mail log file. Additionally, I need to know which tutorial was used to install the server.

Yes I know there is no visible error in the log.
But I can not access the web mail on any possible links he found there.
The ip of my server does not seem blaklisted.
I just sent an email to test if I have not come back because the email does not work.
But to see if it has arrived Iwould love had the web mail .
You would have a suggestion on this?